<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">
        <button v-on:click="count--">-</button>
        <span>{{ count }}</span>
        <button @click="count++">+</button>
    </div>

    <!-- 2. 导入vue.js -->
    <script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
    
    <script>
        const app = new Vue({
            el: '#app',
            data: {
                count: 100
            }
        })
    </script>
</body>
</html>